Symptoms of a bad CIS ECU

[Scott R]

I'm sure this is a limited group of people, however I'm looking for people that have had bad CIS "ecu's" referred to as the "o2 computer" "o2 controller" and "enrichment controller." But basically the unit under the passenger seat that controls the frequency valve and takes the input from the O2 sensor.

I have a hot cycling issue that stops when the O2 sensor is disconnected. Fuel pressures are all in perfect spec, mixture is also in spec as measured on professional machine.

The hot cycling issue is a problem where if the car is shut down after running it starts back up and cycles between 950 and 1200 for about sixty seconds with the o2 sensor connected. With it disconnected it does not do this.

The CIS system is rebuilt, new WUR, fuel distributor lines, injectors seals and all. (this was a result of my fire last summer) The car is making great power with the correct hydrocarbons with the O2 system disconnected.

How can I tell if the ECU is bad? I'm down to that or a wiring issue somewhere.